Papers by ahmad. reza Hooshmand
This paper proposes an efficient joint secret key encryption-channel coding cryptosystem, based o... more This paper proposes an efficient joint secret key encryption-channel coding cryptosystem, based on regular Extended Difference Family Quasi-Cyclic Low-Density Parity-Check codes. The key length of the proposed cryptosystem decreases up to 85 percent using a new efficient compression algorithm. Cryptanalytic methods show that the improved cryptosystem has a significant security advantage over Rao-Nam cryptosystem against chosen plaintext attacks, benefiting from an improvement on the structure of the Rao-Nam cryptosystem and proper choices of code parameters. Moreover, the proposed cryptosystem benefits from the highest code rate and a proper error performance.
IEEE Wireless Communications Letters, 2017
This letter presents an efficient polar code-based physical layer encryption (PLE) scheme with a ... more This letter presents an efficient polar code-based physical layer encryption (PLE) scheme with a short key length in comparison to the conventional symmetric key cryptosystems. By using the properties of polar codes, we consider several efficient techniques to reduce the key length and the computational overhead of the presented PLE scheme. Moreover, the results of the security analyses show that the proposed scheme has a high level of security against conventional attacks on the PLE schemes. In fact, reducing the key length and the computational overhead of the presented PLE scheme has no effect on its security level, which makes it suitable for secure mobile communication devices with limited resources.
IET Communications, 2017
In this study, the secret polar encoding and secret successive cancellation decoding algorithms a... more In this study, the secret polar encoding and secret successive cancellation decoding algorithms are introduced; with these algorithms, secure and efficient communication can be enhanced between the honest parties. Also, the key size of the proposed polar code-based secure channel coding system is reduced significantly compared to the existing systems. To decrease the key size, the authors employ the three following methods: (i) a new approach is proposed to save some bitchannel indices instead of saving the generator matrix of the used polar code; (ii) the permutation and scrambling matrices are not used in this scheme; and (iii) by the help of the properties of polar codes, it does not need to save any vector as part of secret key set to generate an error vector. Moreover, the security analyses demonstrate that this system is resistant against conventional attacks on symmetric-key code-based cryptosystems. It means that reducing the key size of the proposed polar code-based scheme does not affect its security level.
IET Communications, 2016
Günümüzde verilerin fazlalaşması ve giderek karmaşık hale gelmesiyle, bilginin tasarımı çok daha ... more Günümüzde verilerin fazlalaşması ve giderek karmaşık hale gelmesiyle, bilginin tasarımı çok daha önem taşımaktadır. Karmaşık ve düzensiz olan bilgiyi planlı ve anlaşılabilir biçime dönüştüren bilgilendirme tasarımının, kendi içinde pek çok farklı uygulama alanı vardır. Çevresel grafik tasarım, bilgilendirme tasarımının kapsamına giren, yerleşik ve güçlü bir geleneğe sahip, kendi içinde çeşitli alt başlıkları olan, geniş ve disiplinler arası bir uygulama alanıdır. Bu makalede, doğal ve yapılandırılmış çevrede yönlendirme, bilgi verme, tanımlama, tercüme etme ve mekan duygusunu arttırma gibi işlevleri olan çevresel grafik tasarımın, amacı, kapsamı, uygulama alanları ve bu alanlardaki nitelik arayışı örneklerle incelenmektedir.
Goldreich-Goldwasser-Halevi (GGH) public key cryptosystem is an instance of lattice-based cryptos... more Goldreich-Goldwasser-Halevi (GGH) public key cryptosystem is an instance of lattice-based cryptosystems whose security is based on the hardness of lattice problems. In fact, GGH cryptosystem is the lattice version of the first code-based cryptosystem, proposed by McEliece. However, it has a number of drawbacks such as; large public key length and low security level. On the other hand, Low Density Lattice Codes (LDLCs) are the practical classes of lattice codes which can achieve capacity on the additive white Gaussian noise (AWGN) channel with low complexity decoding algorithm. This paper introduces a public key cryptosystem based on LDLCs to withdraw the drawbacks of GGH cryptosystem. To reduce the key length, we employ the generator matrix of the used LDLC in Hermite normal form (HNF) as the public key. Also, by exploiting the linear decoding complexity of the used LDLC, the decryption complexity is decreased compared with GGH cryptosystem. These increased efficiencies allow us to use the bigger values of security parameters. Moreover, we exploit the special Gaussian vector whose variance is upper bounded by the Poltyrev limit as the perturbation vector. These techniques can resist the proposed scheme against the most efficient attacks to the GGH-like cryptosystems.
IET Communications, 2015
In this study, by exploiting the properties of finite-length polar codes, the authors introduce a... more In this study, by exploiting the properties of finite-length polar codes, the authors introduce a physical layer encryption scheme to make secure (from a computational security perspective) and efficient communication between a sender (Alice) and a legitimate receiver (Bob) against both active and passive attacks, simultaneously. To prevent active attacks, two techniques are considered: (i) a novel method is introduced to keep the generator matrix of polar code secret from an active attacker (Oscar); (ii) a proper joint polar encoding/encryption algorithm based on the hidden generator matrix is introduced. Two additional strategies are considered against passive attacks: (i) a new method is introduced to partition the bit-channels into good and bad bit-channels and then the scrambled information bits are transmitted over those bit-channels that are good for Bob but bad for a passive attacker (Eve); (ii) the secret key cryptography is implemented at the physical layer, such that Eve cannot decode the eavesdropped data without the knowledge of the secret key shared between the authorised parties. Besides, this study discusses efficiency analysis results consisting key size, error performance and computational complexity of the proposed scheme.
Wireless Personal Communications, 2015
2013 10th International ISC Conference on Information Security and Cryptology (ISCISC), 2013
This manuscript proposes an efficient secret key cryptosystem based on polar codes over Binary Er... more This manuscript proposes an efficient secret key cryptosystem based on polar codes over Binary Erasure Channel. We introduce a method, for the first time to our knowledge, to hide the generator matrix of the polar codes from an attacker. In fact, our main goal is to achieve secure and reliable communication using finite-length polar codes. The proposed cryptosystem has a significant security advantage against chosen plaintext attacks in comparison with the Rao-Nam cryptosystem. Also, the key length is decreased after applying a new compression algorithm. Moreover, this scheme benefits from high code rate and proper error performance for reliable communication.
Wireless Personal Communications, 2016
McEliece and Goldreich–Goldwasser–Halevi (GGH) cryptosystems are two instances of code and lattic... more McEliece and Goldreich–Goldwasser–Halevi (GGH) cryptosystems are two instances of code and lattice-based cryptosystems whose security are based on the hardness of coding theoretic and lattice problems, respectively. However, such cryptosystems have a number of drawbacks which make them inefficient in practice. On the other hand, low density lattice codes (LDLCs) are practical lattice codes which can achieve capacity over additive white Gaussian noise channel and also can be encoded and decoded efficiently. This paper introduces a public key cryptosystem based on Latin square LDLCs, by which a relationship can be attained between code and lattice-based cryptography. In this way, we can exploit the efficient properties of codes and lattices, simultaneously to improve the security and efficiency of the proposed scheme. For instance, the security of this scheme is based on the hard problems related to lattices, i.e., closest vector problem and shortest basis problem, which in turn lead to increase the security level. On the other hand, we exploit the low complexity decoding algorithm of LDLCs to reduce the computational complexity. Moreover, this property allows using the larger values of the codeword length. Also, we use the special Gaussian vector, whose variance is upper bounded by Poltyrev bound, as the perturbation (error) vector. These strategies make the proposed scheme to be secure against the conventional cryptanalytic attacks.
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Papers by ahmad. reza Hooshmand